The present invention relates to a machine unit comprising a refrigerating compressor and an internal combustion engine of the trochoid type including pistons revolving in a planetary arrangement on eccentrics of the same eccentric shaft, as well as a ventilatable intermediate sealing means arranged in a central casing element between the casing elements of said internal combustion engine and said compressor, around said eccentric shaft, as well as a main bearing for both machines, with the compressor being taper-bore mounted.
Such machine sets or units are used, for instance, in heat pump systems. In such installations, the casings of the compressor and the internal combustion engine, which are interconnected through the eccentric shaft, must be safely sealed against leakage relative to each other so as to prevent any aggressive refrigerant from penetrating into the power or working compartments of the internal combustion engine. The fact must be considered that loads act upon these intermediate sealing means at pressure levels as high as up to 5 bar and more. Regarding the taperbore mounting arrangement of the compressor there should be noted that tumbling movements of the piston will be avoided. This elimination of an outside bearing for compressor support serves the purpose of reducing the axial extension of this unit while a maximum of compact and space-saving design will be achieved. On the other hand, such an approach is inevitable due to the fact that with the given compressor dimensions the small design of the shaft diameter is due to the small diameter of the pinion.
The published German patent application DT-OS 35 03 039.9-Eiermann dated July 31, 1986, belonging to the assignee of the present invention, describes a bearing and shaft arrangement which can be applied in the afore-described machine unit. This intermediate sealing means is arranged beside the compressor and outside of the main bearing so as to communicate directly with the pressurized compressor compartments. This arrangement entails the disadvantage that the compressor eccentric is spaced from the main bearing by a major distance determined by the axial length of this intermediate sealing means, which involves the risk of tumbling movements of the compressor piston as a result of shaft deflection. Moreover, the main bearing is positioned at the hot engine which is dangerous for its oil supply.